Systems in which fluid flows often include at least one filter through which the fluid will flow. The filter removes any debris that inadvertently finds its way into the fluid. For example, a lubrication system in which a lubricant flows will typically have one lubricant filter for catching debris as it is recirculated through the lubrication system. In many applications, an auxiliary lubrication system is connected to the main lubrication system, but is capable of being isolated from the main system under certain operating conditions. Such an auxiliary lubrication system must either have its own filter (separate from the main lubrication system filter) or other accommodations for capturing debris. This increases the size, weight and cost of the system, and additionally creates the need for additional maintenance of the system since the filter will need to be cleaned and/or replaced on some predetermined schedule. Accordingly, improvements in filtering for auxiliary fluid flow systems are needed.